The present invention relates generally to internal combustion engines. More particularly, the present invention relates to uniflow scavenging internal combustion engines.
An engine may be defined generally as a cyclical device used for power production. Most readers will be familiar with the internal combustion engines that have been widely used in automotive applications. A typical automotive engine includes a plurality of pistons, each residing in a separate cylinder. Each piston is coupled to a crankshaft by a piston rod. The typical automotive engine includes a large number of parts. The large number of parts has an impact on the expense of building or fabricating automotive engines, and on the reliability of the engines (e.g., since there are a large number of parts, the likelihood that one of them will fail is increased.) The large number of parts and complexity of the typical automotive engine also has the effect that this type of engine is typically not applicable to very small (i.e., miniature or micro) applications and not economically feasible.
The present invention relates generally to internal combustion engines. More particularly, the present invention relates to uniflow scavenging internal combustion engines. An engine in accordance with one embodiment of the present invention comprises a housing defining an elongated cavity. The elongated cavity has a first end, a second end, and internal walls extending therebetween. A fixed piston is located in the cavity and fixedly attached to the housing. The fixed piston has a first end toward the first end of the cavity and a second end toward the second end of the cavity.
A slider is slidably disposed within the cavity. The slider has a first end toward the first end of the cavity and a second end toward the second end of the cavity. The slider further has a central channel for slidably receiving the fixed piston. The central channel has a first end adjacent the first end of the fixed piston and a second end adjacent the second end of the fixed piston. A first combustion chamber is defined by a space between the first end of the channel and the first end of the fixed piston. A second combustion chamber is defined by a space between the second end of the channel and the second end of the fixed piston.
The housing also defines a first intake port and a second intake port. The first intake port is preferably in fluid communication with a first intake space defined by the space between the first end of the slider and the first end of the cavity when the slider is slidably disposed toward the second end of the cavity. The second intake port is preferably in fluid communication with a second intake space defined by the space between the second end of the slider and the second end of the cavity when the slider is slidably disposed toward the first end of the cavity.
The housing also defines a first exhaust port and a second exhaust port. The first exhaust port is preferably in fluid communication with the first combustion chamber when the slider is slidably disposed toward the first end of the cavity. The second exhaust port is preferably in fluid communication with the second combustion chamber when the slider is slidably disposed toward the second end of the cavity.
The housing also defines one or more first intake channels and one or more second intake channels. The first intake channels provide a fluid flow path between the first intake space and the first combustion chamber when the slider is moved toward the first end of the cavity. The second intake channels provide a fluid flow path between the second intake space and the second combustion chamber when the slider is moved toward the second end of the cavity.
In a preferred embodiment, the engine is configured such that the first intake space may be selectively placed in fluid communication with the first combustion chamber. In this preferred embodiment, the motion of the slider may be used to pump a combustible charge from the first intake space into the first combustion chamber. The first intake space and the first combustion chamber may be configured such that compression of the combustible charge within the first combustion chamber causes the combustible charge to ignite by spontaneous combustion.
An engine in accordance with another embodiment of the present invention comprises a housing having an elongated cavity. The elongated cavity has a first chamber, a second chamber and a third chamber. The first chamber is separated from the second chamber by a first wall and the second chamber is separated from the third chamber by a second wall. A first channel then extends through the first wall between the first chamber and the second chamber and a second channel extends through the second wall between the second chamber and the third chamber.
The engine also includes a piston assembly having a first piston portion, a second piston portion and a third piston portion. The first piston portion is attached to the second piston portion via a first connecting member and the second piston portion is connected to the third piston portion via a second connecting member. The first piston portion is slidably positioned within the first chamber, the second piston portion is slidably positioned within the second chamber, and the third piston portion is slidably positioned within the third chamber. The first connecting member extends through the first channel and the second connecting member extending through the second channel of the housing. A first combustion chamber is defined by a space between the first piston portion and the first wall, and a second combustion chamber defined by a space between the third piston portion and the second wall.
The housing further includes a first exhaust port, a second exhaust port, and an intake port. The intake port is preferably in fluid communication with the second cavity when the second piston portion is slidably positioned either toward the first wall or second wall. The first exhaust port is preferably in fluid communication with the first combustion chamber when the second piston portion is slidably positioned toward the first wall. The second exhaust port is preferably in fluid communication with the second combustion chamber when the second piston portion is slidably positioned toward the second wall.
A first intake space is defined between the second piston portion and the first wall, and a second intake space is defined between the second piston portion and the second wall. One or more of first intake channels preferably extend between the first intake space and the first combustion chamber when the second piston portion is slidably positioned toward the first wall. One or more of second intake channels also preferably extend between the second intake space and the second combustion chamber when the second piston portion is slidably positioned toward the second wall.
It is contemplated that the engine of the present invention may be formed on a larger scale using conventional casting techniques or on a smaller micro scale using integrated circuit processing techniques.